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2.8 to 3.4 parts interchange by tshark
Started on: 01-17-2015 06:45 PM
Replies: 16 (1064 views)
Last post by: LostNotForgotton on 01-19-2015 09:28 AM
tshark
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Report this Post01-17-2015 06:45 PM Click Here to See the Profile for tsharkSend a Private Message to tsharkEdit/Delete MessageReply w/QuoteDirect Link to This Post
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[This message has been edited by tshark (edited 09-08-2018).]

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Report this Post01-17-2015 09:42 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
There are a lot of versions of the 3.4 Are you talking about the 93-95 Camaro/Firebird engine?
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tshark
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Report this Post01-17-2015 10:22 PM Click Here to See the Profile for tsharkSend a Private Message to tsharkEdit/Delete MessageReply w/QuoteDirect Link to This Post
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[This message has been edited by tshark (edited 09-08-2018).]

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Raydar
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Report this Post01-17-2015 10:50 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's easier to list what won't interchange.
Essentially the short block, including the rotating assembly. That's it.

There are a few subtle (PITA) differences.
The 2.8 has a boss cast into the block on the front facing (left) side of the block, where the bottom of the A/C compressor bracket and the bracket for the little shock absorber is fastened. There is a fix for that. I'll try to find a link, and post it here.
After drilling the holes for the starter and screwing in a fitting to adapt the oil pressure sender line, everything else bolts on. Everything.
The Fiero 2.8 and the 3.4 heads are identical, and can be used interchangeably.
All intake and exhaust manifold pieces, timing cover, water pump, and accessory brackets (except for the previously mentioned lower A/C bracket) will bolt right on.
The only real exception is that the 3.4 requires a flex plate or flywheel from an 88 2.8, or later 3.1 or 3.4. The 87 and earlier 2.8s were externally balanced, with a weight on the flywheel.

You asked specifically about the cold start injector. I believe that the 3.4 lower intake and fuel rail are essentially the same as the 2.8 pieces, except that they delete the cold start injector. If you don't want to use the CS injector, you can probably use the 3.4 lower intake and fuel rail. If you do want it, the 2.8 intake will bolt right on.

You will likely need bigger injectors for the 3.4. It'll run on the 2.8's injectors, but it will run lean at high RPM unless you run the fuel pressure way up.
The trick will be finding 17 lb pintle type injectors. The Fiero ECM isn't set up to play nicely with disk type or multec injectors.
There is a programming fix for this. It has been published here, but I couldn't tell you where to find it.
(Accel used to sell 17 lb pintle type injectors. Don't know if they still do, or not.)
Several people who I know have come up with pintle type injectors that are supposed to be 17#, but a scan tool shows that they run as lean as the stock 15# injectors.

Hope that helps a bit.

Edit - Read this. http://www.thefierofactory.com/34.php
And this. (This is one of the best write ups I have ever seen. And it's recently updated.) http://fiero34swap.eleventenths.org/

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Raydar
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Praise the Lowered!

[This message has been edited by Raydar (edited 01-18-2015).]

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fierofool
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Report this Post01-17-2015 11:04 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Everything bolted on the 2.8 will bolt onto the 3.4 pushrod engine. The starter will need to be relocated to the left side using Rodney Dickman's starter relocation jig and you will need to remove a small portion of the starter boss on the right side of the engine. You'll also need to obtain a flex plate from an 88 Fiero if you stay with the TH125C transmission. In any event, the portion of the right side starter boss will need to be removed for use with an automatic.

If you have the 3.4 oil pan, use it, otherwise you'll need to notch out the baffle in the bottom to clear the oil pump. If your engine is an 87 or 88, you can use that pan and timing cover but must notch the baffle. With the 3.4 pan, you must use an 87 or 88 timing cover.

We had a How-To 3.4 swap on the Georgia website, but the link's now dead. I think I got it from doublec4 or Fierohoho.

Sorry, Steve. I was searching for that link while you were posting. Didn't mean to duplicate you.

[This message has been edited by fierofool (edited 01-17-2015).]

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Raydar
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Report this Post01-18-2015 01:50 AM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fierofool:
...
Sorry, Steve. I was searching for that link while you were posting. Didn't mean to duplicate you.



The more the merrier.
Besides, you covered some stuff that I missed. It's been a while, so I have forgotten some stuff.

[This message has been edited by Raydar (edited 01-18-2015).]

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tshark
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Report this Post01-18-2015 07:36 AM Click Here to See the Profile for tsharkSend a Private Message to tsharkEdit/Delete MessageReply w/QuoteDirect Link to This Post
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[This message has been edited by tshark (edited 09-08-2018).]

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Report this Post01-18-2015 01:05 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you use a 3400 block instead you won't have to drill starter holes... I had an A/C bracket on mine so I don't think there is an issue with that unless the guy who did the swap just figured it out. I think one or two bolt holes for the timing cover are bigger so the cover needs to get drilled out and bigger bolt used. You also need to plug a certain hole on the timing cover.

The 3400 advantage is you get a much better cam than the Fiero/Camaro cam when used with 1.6 roller rockers like the 3400 engines use.

You also need to remove the heat shield on the lower intake to clear the roller lifter guides that are on the 3400 block and you need 5.85" pushrods.

So there's some added cost but 3400's are easier to find and the cam upgrade is great!

The added costs are:
rebuild with Camaro 3.4 pistions
get 5.85" pushrods
get narrow body 1.6 roller rockers, I also got the stud adapters to convert from 10mm to 3/8" for the rockers...

I personally have all salvage engines rebuilt as a rule so...not a big deal there, the other costs are the same as replacing old parts with new parts...more or less
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Report this Post01-18-2015 01:57 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by lou_dias:

If you use a 3400 block...
<snip>


This is way beyond the attention span of most folks here. Myself included. Lots of mix-matching and parts sourcing. The CamaroBird block won't make as much power, but it's stone simple to do. If someone has never done this before, it's a good place to "get your feet wet".

If I wanted to go to that much trouble, I'd just bolt in a 3500 or 3900 and worry about the wiring/programming instead.

[This message has been edited by Raydar (edited 01-18-2015).]

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Report this Post01-18-2015 04:03 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Raydar:
This is way beyond the attention span of most folks here. Myself included. Lots of mix-matching and parts sourcing. The CamaroBird block won't make as much power, but it's stone simple to do. If someone has never done this before, it's a good place to "get your feet wet".

If I wanted to go to that much trouble, I'd just bolt in a 3500 or 3900 and worry about the wiring/programming instead.

I think we'd just have to agree to disagree.
Drilling starter holes required it's own set of tools. There are no wiring issues with using a 3400 block over a 3.4 block and I wouldn't trust a used 3.4 engine from a 93-95 F-body to still have good compression 19-21 years later. I know my 98k 2.8 (which has been baby'd) in my Formula does not. Hence a rebuild prior to putting a "3.4" in any car should be considered a "must".

Also, to the OP:
a lot of people use cheap used Mustang 5.0 injectors in 3.4 swaps... Those in a Fiero act like 22# injectors and require the base injector pulse width to be turned down about 21% to work right.
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Report this Post01-18-2015 04:31 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by lou_dias:

........................snip

Also, to the OP:
a lot of people use cheap used Mustang 5.0 injectors in 3.4 swaps... Those in a Fiero act like 22# injectors and require the base injector pulse width to be turned down about 21% to work right.


The first 3.4 swap I was involved with, I bought the Mustang injectors and the car ran very rich. I used the stock Fiero regulator and pump.

The next one, I used the Firebird 17# Rochester Multec injectors and that one ran even more rich. Badly enough that driving behind it was a problem. I went back to the stock Fiero 15# injectors and they are serving him well.

The third one, I got some modified pintle injectors that were used in a BMW V8. They were rated at 17# at the stock Fiero regulator pressure of 43.5 psi. They run slightly lean, but they have never been an issue in the 3 or 4 years I've been running the engine. I got the injectors from FuelinjectorConnection.Com in Cumming, Ga. Fuel Injector Connection can also rebuild and modify your stock Fiero injectors to flow the required 3.4 rating of 17#.
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Report this Post01-18-2015 05:09 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fierofool:


The first 3.4 swap I was involved with, I bought the Mustang injectors and the car ran very rich. I used the stock Fiero regulator and pump.

The next one, I used the Firebird 17# Rochester Multec injectors and that one ran even more rich. Badly enough that driving behind it was a problem. I went back to the stock Fiero 15# injectors and they are serving him well.

The third one, I got some modified pintle injectors that were used in a BMW V8. They were rated at 17# at the stock Fiero regulator pressure of 43.5 psi. They run slightly lean, but they have never been an issue in the 3 or 4 years I've been running the engine. I got the injectors from FuelinjectorConnection.Com in Cumming, Ga. Fuel Injector Connection can also rebuild and modify your stock Fiero injectors to flow the required 3.4 rating of 17#.


reprogramming the ECM seems like a cheaper and easier solution than swapping injectors three times.

I feel like putting iron heads on a 3400 for performance is backwards. it takes more work for something that will most likely under perform.

The 3400 aluminum heads flow way better than the stock iron heads (2.8 or F-body 3.4) they use a canted valve design that moves the valve away from the cylinder wall improving flow. The combustion chambers offer improvements too, being more of a "Fast burn" design than the early heads, they are less prone to detonation than the iron heads. they do require you to use the 3400 intakes, but the fiero intakes are documented as being detrimental to performance, and a poor design.

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"The day I tried to live, I stole a thousand begger's change and gave it to the rich."
http://www.fiero.nl/forum/Forum2/HTML/119122.html

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Report this Post01-18-2015 05:24 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
These were 3 different engines and cars. Actually, 4 engines. The engine for the second car was in such poor condition that we had to replace several pistons and rings. It was supposed to have been a 21,000 mile rebuild so we didn't check it out before the initial install. At that time we went back to the Fiero injectors. Eventually we took that engine out due to lack of oil pressure and put a stock 2.8 back in.

The first engine was a reman 3.4 long block. It's still on the road after about 7 years. Still running rich. And of course, the second one is now running a stock 2.8. The third 3.4 is one of my cars and is doing well with the BMW injectors.
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LostNotForgotton
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Report this Post01-18-2015 09:55 PM Click Here to See the Profile for LostNotForgottonClick Here to visit LostNotForgotton's HomePageClick Here to Email LostNotForgottonSend a Private Message to LostNotForgottonEdit/Delete MessageReply w/QuoteDirect Link to This Post
I did a few videos of some basic 3.4 pushrod conversion processes using basic tools. Maybe you'll find some of the videos a visual guide on your engine swap. I hope this helps

You can start with removing the engine step-by-step:


Relocating the starter


Adding the Fiero distributor to the 3.4 block


Adding the oil pressure sending unit to the 3.4 block


Oil level tube/adapter


3.4 oil pan conversion


Timing chain conversion


Cutting the 3.4 block in order to clear the Fiero AUTOMATIC transmission (not necessary if you have a manual transmission).


Converting the Fiero fuel rail from 15lbs injectors to 17lbs injectors


My very first test start. Got the engine close enough to the car to plug it in to see if it would start once I proved it ran I continued the engine installation. I didn't want to get it in only to find it had to come back out. The jerkiness I had in the first test drive was a bad aftermarket ignition module.
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LostNotForgotton
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Report this Post01-18-2015 10:04 PM Click Here to See the Profile for LostNotForgottonClick Here to visit LostNotForgotton's HomePageClick Here to Email LostNotForgottonSend a Private Message to LostNotForgottonEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you have the extra time and a few hundred extra bucks I'd also suggest upgrading your stock ECM to the 1227730 ECM. There is another thread on the benefits of it you can look up. Here is a video of the conversion process. It's a bit ong and dry but helpfull I think.


Just some fun side videos to check out regarding the 3.4 pushrod engine in a Fiero

Fiero 3.4 0-60 test against an 88 MERA


Autocrossing a 3.4 Fiero with the 7730 ECM swap

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Gall757
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Report this Post01-18-2015 11:07 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
I'd say welcome to the Forum Mr. Lost, but it seems you know your way around here already.

[This message has been edited by Gall757 (edited 01-18-2015).]

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LostNotForgotton
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Report this Post01-19-2015 09:28 AM Click Here to See the Profile for LostNotForgottonClick Here to visit LostNotForgotton's HomePageClick Here to Email LostNotForgottonSend a Private Message to LostNotForgottonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Gall757:

I'd say welcome to the Forum Mr. Lost, but it seems you know your way around here already.



Thanks!! I'd like to think that I know my way around Fiero's about as much as I know my way around the forum

Yeah I tried signing up years ago but at the time the forum wouldn't allow the use of anonymous emails (i.e. Yahoo, Hotmail, Gmail, etc) so I wasn't able to create an account. I was left to just stalk the forums. It wasn't until last month that I saw V8Dreamer was selling an engine I needed AND was close enough for me to pick up that I tried again. This time I was able to finally create an account. After singing up I got the 4.9 Caddy engine as well as a 3800sc engine off of V8Dreamer so now I look forward to doing a video log of my first 3800 conversion
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